问题描述
我正在文件中存储一些数据，但是之后
i am storing some data in the file but after
达到
我重新打开文件并读取矢量中的所有数据，然后存储更新的数据，但是但是实际上该程序不会进入下面的循环.
is reached i reopened the file and reading all data in a vector and then storing updated data butBut actually the program is not going into the below loop.
// Cmarkup1.cpp : This file contains the 'main' function. Program execution begins and ends there.
//
#include <iostream>
#include"Markup.h"
#include <msxml.h>
#include <ctime>
#include <unordered_map>
#include <cctype>
#include <string>
#include <functional>
#include <algorithm>
#include "functions.h"
#include <map>
#include <fileapi.h>
using namespace std;
int main()
{
// Open the file for parsing.
ofstream wfile("title.txt");
bool check = false;
string delimiter = " ,:,";
int results = 0, pages = 1;
time_t timer;
timer = clock();
CMarkup xmlfile;
unordered_map<string, string> titlemap;
unordered_map<string, string> textmap;
vector <string> words;
xmlfile.Load(MCD_T("simplewiki-latest-pages-articles.xml"));
xmlfile.FindElem();
xmlfile.IntoElem();
int line=0;
while (xmlfile.FindElem(MCD_T("page"))) {
xmlfile.IntoElem();
xmlfile.FindElem(MCD_T("title"));
MCD_STR(title);
title = xmlfile.GetData();
string str(title.begin(), title.end());
transform(str.begin(), str.end(), str.begin(), ::tolower);
split(words, str, is_any_of(delimiter));
for (int i = 0; i < words.size(); i++) {
if (titlemap.count(words[i]) == 1) {
ifstream rfile;
rfile.open("title.txt");
vector<string> vec;
string line;
while (getline(rfile, line)) {
vec.push_back(line);
}
for (int j = 0; j < vec.size(); j++) {
if (words[i] == vec[j]) {
cout << vec[j] <<"Checking"<< endl;
wfile << vec[j] << ",page" << pages << endl;
}
else
wfile << vec[j] << endl;
//wfile.close();
}
}
else {
//wfile.open("title.txt");
keeponlyalphabets(words[i]);
titlemap.insert(make_pair(words[i], words[i]));
wfile << words[i] <<"-page"<<pages<< endl;
++line;
}
}
words.clear();
//cout << str << endl;
//xmlfile.FindElem(MCD_T("text"));
//MCD_STR(text);
//text = xmlfile.GetData();
//string str1(text.begin(), text.end());
//transform(str1.begin(), str1.end(), str1.begin(), ::tolower);
//str1 = keeponlyalphabets(str1);
//removestopwords(str1);
//textmap.insert(make_pair(str1, str1));
//cout << str1 << endl;
if (pages > 100)
break;
pages++;
xmlfile.OutOfElem();
}
wfile.close();
// for (auto it : titlemap)
// cout << it.first << endl;
cout << "Total lines are as: "<<line << endl;
/*string input;
cout << "press s to seach the data" << endl;
getline(cin, input);
if (input == "s") {
string key;
cout << "Enter Key" << endl;
cin >> key;
transform(key.begin(), key.end(), key.begin(), ::tolower);
size_t temp;
cout << endl;
for (auto it = data.begin(); it != data.end(); it++) {
//temp = it->first.find(key);
//cout << temp;
if (it->first.find(key) != std::string::npos) {
cout << it->second << endl;
results++;
}
}
}
else
cout << "Invalid Character Exiting....." << endl;
timer = clock() - timer;
cout << "Total time taken by the process is: " << (float)timer / CLOCKS_PER_SEC << endl;
cout << " Total Results : " << results << endl;
*/
return 0;
}
推荐答案
您已针对文件打开了单独的流，每个流上都有单独的缓冲区.对文件的 write 写入实际上实际上很少写入磁盘(通常是在缓冲区已满时，这可能需要一段时间才能进行较小的写入，并且总是在关闭文件之前).因此，当您重新打开文件进行读取时，它不会看到任何残留在用户空间缓冲区中的东西.
You have separate streams opened against the file, with separate buffers on each. writeing to a file only actually writes to disk infrequently (typically when a buffer fills, which may take a while for small writes, and always just before the file is closed). So when you re-open the file for read, it won't see anything still stuck in user-space buffers.
只需添加:
wfile.flush()
在打开以进行读取之前，请确保将缓冲区刷新到磁盘上并供备用句柄使用.
prior to opening for read, to ensure the buffers are flushed to disk and available to the alternate handle.
这篇关于从同一文件读取和写入?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！